PHYS 202 1st EditionExam # 2 Study GuideLecture 10 Magnetic ForceWhat is the relationship of magnetic fields, force and charge? How is the right hand rule used todetermine the direction of the force and how does charge affect it?- Force= |charge|velocity x magnetic force and magnetic fields exert force only on movingcharges and charge is proportional to the magnetic force. A permanent magnet, a moving charge, and a current all create magnetic fields- Allow the tips of your fingers to point in the direction of the velocity. Then move your palm so it faces the direction of the magnetic field. Wherever your thumb is pointed is the direction of the force if the charge is positive. However, if the charge is negative it is the opposite.Lecture 11 TorqueWhat is the relationship between magnetic fields in circular motion? What is cyclotron frequency? What is the equation for magnetic force on a current carrying conductor? What is the relationship of force and torque on a current loop?- The larger the magnetic field the smaller the radius. If the charge is negative the particles moves counterclockwise. The angular velocity (w) of a particle in circular motion is v/R=|q|B/m- It is the number of revolutions per unit time and the frequency is independent of the radius- The force is perpendicular to the conductor and the field and the force= current (I) x length x uniform magnetic field (B) sin(the angle between the current and magnetic field). So if the magnetic field is reversed so is the direction of the force and the same applies for the current. The force in this equation is independent of the sign of the charge.- Force=current x length X B cos(angle). The loop is at stable equilibrium when angle equals 0 and at unstable equilibrium when it is at 180. The torque is at its max when angle=90. Torque=IaB(bsin(angle)). The product of Iab=I(Area)=mu= magnetic momentLecture 12 Fields of wiresWhat is the relationship of a magnetic field to current on a straight wire? What is the relationship between a circular loop exists? What is a solenoid? What happens when 2 current carrying conductors are parallel?- B=(mu(I))/(2piR) where the magnetic field is equivalent at every point on the wire.- If there is a moving current then a magnetic field would exist. A circular loop would have a magnetic field B=(mu(I))/2R and the field would be the strongest inside the loop.- Solenoids are helical winding of wire and the torque of a solenoid can be found using theequation NIABsin(angle between the normal to the loop and B). The magnetic field is found using the equation B=mu(n)I where n=N/L- If the conductors carry the current in the same direction they are attracted to each other. They repel each other if the currents are opposite. The force per unit length that the conductors exert on each other is calculated using the equation F/l=muII’/2piRLecture 13 Induced EMFWhat is magnetic flux? What is Faraday’s Law? What is the sinusoidal relationship of EMF? What is Lenz’s Law? - Magnetic flux is the relationship of the magnetic field to the area and is measure in Webers and magnetic flux density is the magnetic flux divided by the change in area. - This law states that the induced emf is directly proportional to the change in time- Magnetic flux and EMF fluctuate between negative and positive as the loop revolves. Magnetic flux is at its greatest at 0 or 180 while EMF is at its greatest at 90 or 270 when parallel to the magnetic field. - This law states that the induced current is opposite to that of the current inducing it the magnetic flux is increasing. If the flux decreases then the current remains in the same direction.Lecture 14InductanceWhat is mutual inductance? What is self-inductance? How do you calculate the energy and power within an inductor?- Mutual inductance is the change in EMF in response to an adjacent current. EMF= M (change in current/ change in time) and is measured with the Henry.- This is when the emf value changes on a conductor because of varying currents within its own magnetic field. Self-inductance (L) is measured using EMF= L(change in current/change in time)- U=0.5LI^2 and P=VI= LI(change in i/change in time)Lecture 15 RL and LC CircuitsWhat are the relationships within an RL circuit? What are the relationships within an LC circuit?- The greater the inductance the more slowly the current increases. L divided by R createsa time constant which is used in the current decay equation where the current i=Ie^(time constant multiplied by time)- As a capacitor increases the I decreases and when the circuit is fully charged and the switch closed the current is 0. Then when the capacitor discharges the I increases. This oscillation in the values of current and capacitor is identified as electrical oscillation (w) where w= 1/squareroot(LC) Lecture 16 AC CircuitsHow do you make an inductor, resistor, or voltage a root means square value? What are the relationship between phasors and the voltage phasor? How do you calculate inductance reactance and the capacitor reactance? How do you calculate impedance?- If you divide the value by the square root of 2 the value becomes rms- The current phasor and voltage source phasor are in phase while the capacitor phasor lags the current phasor by 90degrees and the inductance phasor leads the current phasor by 90degrees. If the phase angle is positive the voltage phasor leads but if the phase angle is negative the voltage phasor lags.- Inductance reactance XL= wL and capacitive reactance XC=1/wC- Impedance (Z)= square root(R^2 + (XL-XC)^2) and the phase angle is found using inverse tan((XL-XC)/R)Lecture 17 Power/Series ResonanceWhat equations can be used to find power in AC circuits? What is resonance?- P=0.5VI and P=(Irms)^2R For a resistor the power is always positive. For inductors and capacitors their power is alternatively positive and negative so the average power is 0.- Resonance is when the current amplitude peaks and impedance is at its minimum. Resonance frequency is w0(aka angular